http://www.fs.fed.us/foresthealth/technology
Forest Health Technology Enterprise Team
P R O V I D I N G T E C H N O L O G Y F O R F O R E S T H E A LT H P R O T E C T I O N
Tree of Heaven Biological Control
Tree of heaven, (Ailanthus altissima) (Mill.) Swingle is
a member of the Simaroubaceae family, and native to
central China. It was first introduced to the United States
in 1784 in Philadelphia, PA. It was later introduced to
gold-mining areas of California in the mid-1800s. Tree
of heaven occurs across the U.S. and is reported to be
invasive in natural areas in at least 30 states.
Nature of Ecological Damage
Tree of heaven is a fast-growing deciduous tree
with an extensive root system and prolific seed
production, making it a serious invasive pest plant
of disturbed urban sites. In rural areas tree of heaven
easily invades cropland, fencerows, forest edges and
forest openings, as well as untillable, rocky areas
where it can form dense thickets crowding out native
vegetation. Moreover, tree of heaven produces
alleopathic chemicals in its root system that prevent
other plants from becoming established near it.
Biology and Traditional Control
Tree of heaven may be confused with several sumac
species (Rhus spp.) as well as butternut and black
walnut (Juglans spp.).The sumacs have red upright seed
clusters as opposed to the samaras of tree of heaven.
Walnut and butternut produce hard-shelled nuts.
Tree of heaven has a thin pale gray bark. It has two
types of branches; sterile long shoots may
be up to 18 feet in length, while short shoots
that produce flowers are only 18 inches in
length. The malodorous, pinnately compound
leaves, may be up to 3 feet long. Fruits are
one-seeded, dry schizocarps similar to maple
(Acer spp.) fruits that are easily wind-dispersed.
The shallow, wide-spread roots produce
root shoots that become dense thickets of
trees. The root shoots may appear up to 90
feet from the parent. Tree of heaven also
sprouts from stumps, root crown and the bole.
Clockwise L to R: Leaves and flowers; colorful, one-seeded shizocarps
and biological control agent, a weevil, Eucryptorrhychus brandti.
Biological Control
In 2004, surveys for natural enemies of tree
of heaven were initiated in China. Following
preliminary host range testing of several
potential agents a host-specific weevil
herbivore, Eucryptorrhyncus brandti was
identified as the most promising natural enemy.
In 2006, a colony of the weevil was established
Forest Health Technology Enterprise Team
http://www.fs.fed.us/foresthealth/technology
P R O V I D I N G T E C H N O L O G Y F O R F O R E S T H E A LT H P R O T E C T I O N
at the quarantine facility of Virginia Polytechnic
Institute and State University in Blacksburg, VA. The
procedures for rearing the weevil and additional host
range testing was completed. A petition for its release
in the U.S. was submitted to the Technical Advisory Group
(TAG) for Biological Control of Weeds in 2011 and their
recommendation was to conduct additional host range
testing which is in progress.
In 2002, a native vascular wilt fungus, Verticillium
nonalfalfae, was observed in Pennsylvania causing
significant mortality to tree of heaven. This fungus has
F OR M O R E INFO RMAT I O N CON TAC T: Richard Reardon, Program Manager
Biological Control & Biopesticides
USDA Forest Service
180 Canfield Street
Morgantown, WV 26505
Phone: 304-285-1566 Fax: 304-285-1564
E-mail: rreardon@fs.fed.us
also been recovered on tree of heaven in VA and OH.
The weevil E. brandti has been shown to
successfully carry and transmit V. nonalfalfae to tree of
heaven. Also a large percentage of surviving weevils
overwintering in the soil were able to carry viable V.
nonalfalfae propagules externally.
Following extensive host range testing, the
fungus is being distributed at various test sites within the
state of Pennsylvania for establishment and developing
infestation. A revised petition has been submitted to the
TAG for release of the weevil.